The T32 Pathophysiology of Human Blood Cells, now in its 32nd year of funding, is seeking renewal to continue a long-standing focus on training physician-scientists in pediatric Hematology/Oncology. The object of the training program is to provide PhD and PhD-post-doctoral level research experiences and scholarly research training in Hematology/Oncology, so as to render trainees independent investigators making substantive contributions to biomedical research. The program has undergone significant changes in the past 2 cycles with the appointment of Drs. David Williams and Ellis Neufeld as Program Director and Co-Director, respectively. New areas of focus established in the past two funding cycles include stem cell biology, platelets/thrombosis, neutrophil biology/innate immunity, red cell biology/hemoglobin expression and an overall emphasis in translational research. In addition, new programs are targeting women in undergraduate science classes and MD/PhD students at Harvard Medical School/MIT to enhance the future pipeline of trainees coming to this T32. The 60 training faculty include outstanding scientists many with exemplary publication and training records. In spite of pressures on the NIH budget, research funds to the training faculty currently total $36,165,934 per year representing 158 NIH grants. The training faculty is highly collaborative, and Boston Children's Hospital, Dana-Farber Cancer Institute, Harvard Stem Cell Institute, Harvard, Harvard CTSA and MIT academic environments provide stellar opportunities for formal coursework and for a myriad of scientific seminars and lectures. Of those applying for positions on this T32, 5% are accepted with a 16% acceptance rate for under-represented minorities, and over the past 15 years, 56 of 89 of our fellows were women. There are formal processes in place for regular trainee and faculty feedback. Success of trainees as judged by success in obtaining NIH training grants and independent faculty positions is outstanding and nearly 100% of entering fellows remain in hematology/oncology in scientific careers. Indeed, graduates of this training program now represent leaders in the field with significant numbers serving in academic or pharmaceutical/biotech leadership positions. This success continues in the latest funded cycle. Of the 36 MD or MD/PhD trainees who began their training at BCH/DFCI within the past 10 years and who are no longer on the grant, 24 (67%) have already obtained career awards or prestigious fellowships and of the 10 PhDs, 9 (90%) have received prestigious fellowships. We are requesting renewal with funding to support 11 training slots in the next funding period.